Learning curve of percutaneous endoscopic interlaminar lumbar discectomy versus open lumbar microdiscectomy at the L5-S1 level

Meta-Analysis of Learning Curve in Endoscopic Spinal Surgery: Impact on Surgical Outcomes

Study DesignSystematic review and meta-analysis.ObjectiveThis meta-analysis aimed to evaluate the learning curve in endoscopic spinal surgery, including the time to mastery and challenges faced by novice surgeons, to improve learning and surgical outcomes.MethodsData extraction included the learning curve period and a comparison of surgeons with more experience or late period of the learning curve (late) and surgeons with less experience and in the early period of the learning curve (early) with respect to demographic, surgical, hospitalization, functional, and complication variables. Statistical analysis was performed using Review Manager 5.4.1 software.ResultsThis meta-analysis included 16 studies (n = 1902). The average number of cases required to reach the learning curve was 32.5 ± 10.5. The uniportal technique required fewer cases (30.1 ± 10.2) than biportal technique (38.7 ± 10.3). There were no significant differences in demographic variables, operation level, or duration of symptoms between the advanced and novice surgeons. Advanced surgeons showed better outcomes in VAS leg pain at less than 6 months (SMD 0.18, 95% CI 0.01-0.34) and >6 months (SMD 0.14, 95% CI 0.02-0.27), as well as VAS back pain at > 6 months (SMD 0.16, 95% CI 0.04-0.29). The incidence of total complications was significantly higher in the novice surgeon group. The specific complications did not differ significantly between the 2 groups.ConclusionsThe average number of cases required to reach the learning curve was 32.5 ± 10.5. Experienced surgeons had shorter surgery and fluoroscopy times, better outcomes in leg and back pain, and a lower incidence of complications than novice surgeons.

Learning Curve of Endoscopic Lumbar Discectomy - A Systematic Review and Meta-Analysis of Individual Participant and Aggregated Data

STUDY DESIGN

A systematic review and meta-analysis of individual participant and aggregated data.

OBJECTIVES

To define the learning curves of endoscopic discectomies using unified statistical methodologies.

METHODS

Searches returned 913 records, with 118 full-text articles screened. Studies of endoscopic lumbar spine surgery reporting outcomes by case order were included. Mixed-effects nonlinear, logistic, and beta meta-regressions prdwere conducted to define the learning curves.

RESULTS

13 studies involving 864 patients among 15 surgeons were included in total. For transforaminal endoscopic discectomy, the estimated operating time for the first case was 95 min [CI: 87-104], and the estimated plateau was 66 minutes [CI: 51-81]. An estimated 21 cases [CI: 18-25] were required to overcome 80% of this deficit, but near-plateau performance was expected only after 59 cases [CI: 51-70]. The estimated risk of surgical complications on the first case was 25% [CI: 11%-46%], with an 80% reduction in relative risk requiring an estimated 41 cases. The expected postoperative VAS leg pain score after the first case was 2.7 [CI: 1.8-3.8], with an 80% improvement requiring an estimated 96 cases. Similar numbers were required to overcome the learning curves in interlaminar and biportal endoscopic discectomies.

CONCLUSIONS

Approximately 60 cases are required to achieve proficiency in endoscopic lumbar spine surgery, although the greatest part of the learning curve can be overcome with 20 cases. This should be considered when designing implementation programmes for surgeons and service providers that wish to incorporate endoscopic spinal surgery into their practice.

Biportal endoscopic lumbar discectomy surgery in patients with cauda equina syndrome caused by lumbar herniated intervertebral disc: a retrospective multi-center cohort study

BACKGROUND

Cauda equina syndrome (CES) is a severe neurological condition caused by significant compression of the cauda equina nerve roots. This study evaluates the efficacy of biportal endoscopic (BE) lumbar discectomy in treating CES caused by lumbar herniated intervertebral discs.

METHODS

This retrospective case series includes 32 CES patients treated with BE lumbar discectomy from March 2017 to July 2022. Patient demographics, surgical details, and outcomes were analyzed. Clinical outcomes were assessed using the Visual Analog Scale (VAS), Oswestry Disability Index (ODI), and EQ-5D scores at baseline, and at 3, 6, and 12 months postoperatively.

RESULTS

The mean age was 44.44 ± 13.70 years. The average duration from symptom onset to surgery was 44.81 ± 32.69 h. Significant improvements at 12 months were observed in VAS for back pain (5.00 ± 2.82 to 1.28 ± 1.63, p < 0.01) and leg pain (7.44 ± 1.79 to 1.16 ± 1.55, p < 0.01), ODI (58.25 ± 20.15 to 10.13 ± 14.54, p < 0.01), and EQ-5D (0.414 ± 0.175 to 0.859 ± 0.163, p < 0.01). Bladder and bowel symptom recovery rates were 86.7% and 85.0%, respectively. Mean operation time was 42.50 ± 17.91 min, with a hospital stay of 3.34 ± 2.59 days. Complications included incidental durotomy (6.3%) and facet joint injury (6.3%).

CONCLUSION

Biportal endoscopic spine surgery is a feasible and effective option for CES, providing significant decompression with minimal tissue damage and a low complication rate.

Endoscopic transfacet Decompression for Severe Lumbar Spinal Stenosis: A Technical Note, Illustrative Clinical Series, and Surgeon Survey Regarding Post-Decompression Instability

Background: Lumbar spinal stenosis (LSS) remains a predominant cause of debilitating back and leg pain, affecting many aging populations. Traditional decompression surgeries can be invasive and pose significant risks and recovery time. This study elucidates the techniques and preliminary outcomes of endoscopic transfacet decompression in treating severe LSS. Methods: A retrospective review was performed on 65 patients with severe LSS who underwent endoscopic transfacet decompression. The patient outcomes were analyzed using the VAS for leg pain and the modified Macnab criteria. Pre-operative and post-operative scores were compared, and any complications were analyzed. An online survey was administered to 868 surgeons using Likert-scale ratings to evaluate surgeons' experience with endoscopic decompression in patients with painful spondylolisthesis. The survey responses were analyzed using descriptive statistics and Polytomous Rasch analysis to evaluate surgeon endorsement. Results: The study included 65 patients, of which 29 (44.6%) were female and 36 (55.4%) were male, with a mean age of 65.79 ranging from 38 to 84 years. The available mean post-operative follow-up period was 31.44 months, ranging from 24 to 39 months. The VAS score for leg pain reduced significantly from pre-operative 7.54 ± 1.67 to 2.20 ± 1.45 by 5.34 ± 2.03 (p < 0.001) with a large effect size (Cohen's d = 2.626). At the final follow-up, functional Macnab outcomes were reported as excellent by 20 (30.8%), good by 37 (56.9%), fair by 5 (7.7%), and poor by 3 (4.6%) of patients. There were no incidental durotomies, nerve root injuries, wound complications, or instances of post-operative instability. Only five patients (7.7%) developed post-operative dysesthesia. Incomplete decompression led to fair and poor outcomes in 8 (12.3%) patients. No revision surgeries were performed. post-operative instability was not observed. The surgeon survey corroborated these observations, where the polytomous Rasch analysis showed consensus on the effectiveness of the percutaneous endoscopic decompression of low-grade spondylolisthesis. Differential item functioning (DIF) analysis showed no significant bias in item responses between orthopaedic and neurosurgeons. Conclusions: The endoscopic transfacet decompression technique delineated herein showcased excellent Macnab outcomes in managing severe LSS, with a combined success rate of 87.7%. Patients also experienced a statistically significant reduction in leg pain. Dysesthesia rates were lower than with the transforaminal approach, likely because of limited exiting and traversing nerve root manipulation. This technique might represent a viable, less invasive alternative to open microsurgical dissection and decompression for patients with severe LSS, where fusion may be required. This approach was found to be highly accepted among endoscopic spine surgeons.

What is the learning curve for endoscopic spine surgery? A comprehensive systematic review

BACKGROUND CONTEXT

Endoscopic spine surgery (ESS) is rapidly emerging as a viable minimally invasive technique to successfully treat symptomatic degenerative spinal conditions. Widespread adoption has been limited in part due to the learning curve.

PURPOSE

To systematically review the learning curve for uniportal and biportal ESS and compare the 2 techniques.

STUDY DESIGN/SETTING

A systematic review based on PRISMA guidelines.

PATIENT SAMPLE

About 29 studies were included with 18 studies investigating uniportal learning curves and 11 biportal studies. There were 1,493 patients across all uniportal studies. There was a total of 1,005 patients across all biportal studies.

OUTCOME MEASURES

Number of patients, technique type, patient reported outcomes, complications, operative time before the learning curve threshold, operative time after learning curve threshold, number of cases required to meet threshold, number of surgeons in the study, and cases per surgeon were collected and analyzed.

METHODS

A comprehensive literature search was conducted using PubMed, Medline, and Embase from 2000 to present date. Data was extracted by 3 independent reviewers.

RESULTS

The learning curve studies were reviewed and summarized. The overall median number of cases to reach the learning curve threshold was significantly less in uniportal vs biportal studies (20 vs. 37.5, p=.0463). When stratifying by various procedures, there was no significant difference between the techniques with number of cases required or improvement of operative time. Operative time for biportal discectomies decreased by a significantly greater amount vs uniportal. (44.5% vs. 21.4%, p=.0332).

CONCLUSIONS

The learning curve literature for ESS was systematically reviewed and ways to overcome the learning curve were discussed. The overall median number of cases for the learning curve was significantly fewer in uniportal vs biportal but the improvement in operative time was significantly greater with biportal discectomies, typically the entry level procedure by novice surgeons. Overcoming the learning curve for ESS is a critical factor to widespread adoption and understanding it may aid surgeons in progressing to proficiency while mitigating the risk of complications.

Evolving Paradigms in Spinal Surgery: A Systematic Review of the Learning Curves in Minimally Invasive Spine Techniques

Our research examines the learning curves of various minimally invasive lumbar surgeries to determine the benefits and challenges they pose to both surgeons and patients. The advent of microsurgical techniques since the 1960s, including advances in fluoroscopic navigation and intraoperative computed tomography, has significantly shifted spinal surgery from open to minimally invasive methods. This study critically evaluates surgical duration, intraoperative conversions to open surgery, and complications as primary parameters to gauge these learning curves. Through a comprehensive literature search up to March 2024, involving databases PubMed, Cochrane Library, and Web of Science, this paper identifies a steep learning curve associated with these surgeries. Despite their proven advantages in reducing recovery time and surgical trauma, these procedures require surgeons to master advanced technology and equipment, which can directly impact patient outcomes. The study underscores the need for well-defined learning curves to facilitate efficient training and enhance surgical proficiency, especially for novice surgeons. Moreover, it addresses the implications of technology on surgical accuracy and the subsequent effects on complication rates, providing insights into the complex dynamics of adopting new surgical innovations in spinal health care.

Development of New Surgical Training for Full Endoscopic Surgery Using 3D-Printed Models

Introduction

Full endoscopic spine surgery continues to spread worldwide but has a long learning curve. Conventional endoscopy training uses live pigs or human cadavers, which has disadvantages such as high costs and limited availability. Therefore, this study aimed to develop and evaluate three-dimensional (3D)-printed models for endoscopy training.

Methods

Models for 3D printing were generated using raw imaging data from 1.0-mm slices of computed tomography scans, and each part was printed using a different colored material. The combined model was used for training as part of the full endoscopy training kit.

Results

This approach offers several advantages. First, it enables the creation of accurate disease models, such as lumbar disc herniation and other abnormalities, which are useful for both surgical training and preoperative simulations. Second, it is useful for learning surgical orientation. During surgical training, the surgical field can be viewed directly through an endoscope or with the naked eye. By using various colors, it becomes easier to recognize the orientation. Third, the amount of drilling resection can be easily confirmed, facilitating feedback. Finally, training for various surgical techniques is possible, including endoscopic holding techniques and using the endoscope's outer sheath to retract nerves. However, this approach also has some disadvantages, such as the lack of bleeding, inability to reproduce tissue hardness, and difficulty in faithfully recreating soft tissue, such as connective tissue, blood vessels, and fat. Therefore, it is difficult to reproduce the hardness of the calcified disc or disc herniation with apophyseal ring fracture. Moreover, 3D-printed models are not suitable for surgical training using the interlaminal approach because it is difficult to perform separation between the ligamentum flavum and dural matter or between the dural matter and intervertebral disc.

Conclusions

3D-printed models are a useful complement to live pigs and human cadavers in surgical training and can reduce the time required to acquire endoscopic skills.

Is Close Supervision by a Senior Surgeon Necessary During the Initial Days of Performing Endoscopic Lumbar Discectomy? A Retrospective Comparative Study between Two Fellowship Trained Surgeons to Assess the Learning Curve

Objectives

Endoscopic lumbar discectomy is a minimally invasive technique with a steep learning curve. The studies in the literature base the learning curve on the operative duration. We conducted this study to determine the learning curve based on the presence or absence of supervision by an experienced surgeon.

Materials and Methods

This study involved two spine surgeons (surgeon A and surgeon B), who after their fellowship training from the same institute started practising in two different hospitals with different settings. The data of the first 80 patients operated by these two surgeons were extracted, and the patients were followed up for a minimum of 1 year. The data were split into first 30 cases and late 50 cases, which were compared to see the difference between the two surgeons.

Results

The first 30 cases were evaluated between the two surgeons, and the most significant difference between the two was the operative duration. There was difference between the two surgeons in approach towards migrated and foraminal/extra foraminal discs (P = 0.02). The surgeon B started operating on upper lumbar levels in his later 50 cases, but the foraminal and extraforaminal disc herniations were rarely treated by surgeon B.

Conclusions

Endoscopic discectomy when supervised by senior faculty helps to reduce the operative duration especially in the initial phases of a surgeon's career. The surgeon under the supervision of a senior faculty performs more of migrated and foraminal herniated discs.

Challenges in Contemporary Spine Surgery: A Comprehensive Review of Surgical, Technological, and Patient-Specific Issues

Spine surgery has significantly progressed due to innovations in surgical techniques, technology, and a deeper understanding of spinal pathology. However, numerous challenges persist, complicating successful outcomes. Anatomical intricacies at transitional junctions demand precise surgical expertise to avoid complications. Technical challenges, such as underestimation of the density of fixed vertebrae, individual vertebral characteristics, and the angle of pedicle inclination, pose additional risks during surgery. Patient anatomical variability and prior surgeries add layers of difficulty, often necessitating thorough pre- and intraoperative planning. Technological challenges involve the integration of artificial intelligence (AI) and advanced visualization systems. AI offers predictive capabilities but is limited by the need for large, high-quality datasets and the "black box" nature of machine learning models, which complicates clinical decision making. Visualization technologies like augmented reality and robotic surgery enhance precision but come with operational and cost-related hurdles. Patient-specific challenges include managing postoperative complications such as adjacent segment disease, hardware failure, and neurological deficits. Effective patient outcome measurement is critical, yet existing metrics often fail to capture the full scope of patient experiences. Proper patient selection for procedures is essential to minimize risks and improve outcomes, but criteria can be inconsistent and complex. There is the need for continued technological innovation, improved patient-specific outcome measures, and enhanced surgical education through simulation-based training. Integrating AI in preoperative planning and developing comprehensive databases for spinal pathologies can aid in creating more accurate, generalizable models. A holistic approach that combines technological advancements with personalized patient care and ongoing education is essential for addressing these challenges and improving spine surgery outcomes.

Unilateral Biportal Endoscopic Discectomy versus Percutaneous Endoscopic Interlaminar Discectomy for Lumbar Disc Herniation

Background

As the latest endoscopic spine surgery, percutaneous endoscopic interlaminar discectomy (PEID) and unilateral biportal endoscopic (UBE) discectomy have distinct technical characteristics. This study aimed to evaluate the clinical outcomes of PEID and UBE discectomy in the treatment of single-level lumbar disc herniation (LDH).

Methods

Between February 2019 and April 2022, 115 patients with single-level LDH at L4-5 or L5-S1 received PEID or UBE discectomy. The patients were separated into two groups based on the surgical method used: Group 1 (the PEID group) (n = 60) and Group 2 (the UBE group) (n = 55). Various parameters, including operative time, hospitalization time, fluoroscopy frequency, total costs, complications, visual analogue scale (VAS), and Oswestry Disability Index (ODI), were evaluated and compared between the two groups.

Results

There were no significant differences in the VAS and ODI scores in 12 months after the operation between two groups (P > 0.05). However, the VAS of lower back pain on the first day after the operation in Group 2 (2.53±0.89) was higher than that in Group 1 (2.19±0.74) (P < 0.05). There were no significant differences in the operation time and incidence of complications between two groups (P > 0.05). But total costs in Group 2 (43,121±4280) were significantly higher than those in Group 1 (30,069±3551) (P < 0.05).

Conclusion

Both UBE and PEID procedures have similar efficacy in alleviating pain and improving functional ability in patients with LDH. However, UBE surgery results in higher costs than PEID surgery.

Outcome of Percutaneous Endoscopic Lumbar Discectomy in Relation to the Surgeon's Experience: Propensity Score Matching

Percutaneous endoscopic lumbar discectomy (PELD) presents a challenging learning curve, and the correlation between surgeon experience and clinical outcomes remains contentious. This retrospective study aimed to compare the outcomes of PELD performed by a single surgeon at beginner and experienced stages. Propensity score matching selected 150 patients (75 per group) with a minimum 3-year follow-up. Clinical and radiological outcomes, perioperative complications, and adverse events were assessed. Baseline characteristics, pain improvement, patient satisfaction, and radiological outcomes did not differ between the groups. However, operation time was longer in the beginner group than in the experienced group (57.5 min [IQR, 50.0-70.0] versus 50.0 min [IQR, 45.0-55.0], p < 0.001). The beginner group had higher perioperative complication rates (eight patients [10.7%] versus one patient [1.3%], with a hazard ratio of 8.836 [95% CI, 1.077-72.514], p = 0.034) and lower 3-year survival without adverse events (19 patients [25.3%] in the beginner group and 10 patients [13.3%] in the experienced group, p = 0.045). Our findings indicate that the clinical outcomes were more favorable in patients operated on at the experienced stage compared to those treated at the beginner stage.

Comparison of biportal endoscopic technique and uniportal endoscopic technique in Unilateral Laminectomy for Bilateral Decomprssion (ULBD) for lumbar spinal stenosis

OBJECTIVE

Unilateral laminotomy for bilateral decompression (ULBD) has been adopted widely to treat lumbar spinal stenosis (LSS). The objective of the study is to investigate clinical and radiological outcomes of the biportal endoscopic ULBD (BE-ULBD) and uniportal endoscopic ULBD (UE-ULBD).

METHODS

We collected retrospectively 65 patients' data who met the inclusion criteria (July 2019-June 2021). 33 patients underwent BE-ULBD surgery, and 32 patients underwent the UE-ULBD surgery, and were followed up for at least 1 year. The following preoperative and postoperative outcomes were compared between groups: the visual analog scale (VAS) for pain, the Oswestry disability index (ODI) for nerve function, and modified Macnab criteria for satisfaction, the cross-sectional area of the dural sac (DSCSA), the mean angle of facetectomy.

RESULTS

Age, BMI, gender, levels of involvement and duration of symptoms were not significantly different at baseline in this study. Clinical data showed that postoperative ODI, VAS scores and Modified Macnab Criteria were not statistically different between the two groups. The BE-ULBD group had a shorter operation time than the UE-ULBD group (P < 0.001). Patients in the BE-ULBD group had a larger postoperative expansion of DSCSA expansion postoperatively (85.58 ± 3.16 mm2 VS 71.43 ± 3.35 mm2, P < 0.001) and a larger contralateral facetectomy angle (63.95 ± 3.34° vs 57.80 ± 3.43°, P < 0.001) compared with patients in the UE-ULBD group. There were no statistical differences in the incidence of postoperative complications between the two groups.

CONCLUSION

Both the BE-ULBD and the UE-ULBD yielded clinical improvement in terms of pain and stenosis symptoms. The BE-ULBD technique has the advantages of the shorter operation time, larger DSCSA expansion and larger contralateral facetectomy angle.

Interlaminar Endoscopic Lumbar Discectomy Versus Microscopic Lumbar Discectomy: A Preliminary Analysis of L5-S1 Lumbar Disc Herniation Outcomes in Prospective Randomized Controlled Trials

OBJECTIVE

A preliminary report from a single institution, noninferiority, prospective randomized controlled trial is conducted to determine the effectiveness of interlaminar endoscopic lumbar discectomy (IELD) versus microscopic lumbar discectomy (MLD) for the treatment of L5-S1 lumbar disc herniation (LDH).

METHODS

This prospective, noncrossover, randomized controlled trials was conducted at a single neurosurgical center. Patients with symptomatic radiculopathy or intermittent neurogenic claudication caused by LDH were enrolled from July 2016 to July 2021. The study compared the effectiveness of microscopic and full-endoscopic discectomy procedures. Outcome measures included visual analogue scale (VAS) scores for back and leg pain, Oswestry Disability Index scores, radiologic measurements, endurance time of walking, and satisfaction rate.

RESULTS

Of 37 assessed patients, both IELD and MLD groups demonstrated significant improvements in VAS scores for pain over time, with no significant difference between them. For secondary outcomes, the IELD group had a shorter hospital stay and reduced blood loss but a longer operation time than the MLD group. Radiographic evaluations showed no change compared to preoperative data. Patient satisfaction and recovery rates were slightly higher for the MLD group, but both groups were comparable in most evaluations, with complications being minimal.

CONCLUSION

The IELD was noninferior in improving the intensity of back and leg pain and functional disability, compared to the MLD. Additionally, the IELD showed no difference in clinical outcomes for patients in terms of radiographic results and patient satisfaction rates. The results of this research preliminarily demonstrate that the IELD could be considered an effective alternative to MLD for L5-S1 central or paracentral LDH.

Comparative analysis of patient-reported outcomes after percutaneous endoscopic lumbar discectomy between transforaminal and interlaminar approach: a minimum two year follow-up

PURPOSE

Percutaneous endoscopic lumbar discectomy has been increasingly used in the treatment of lumbar disc herniation. However, there is no consensus on which method would be more effective between the transforaminal and interlaminar approach.

OBJECTIVE

To compare clinical outcomes, patient satisfaction rate, reoperation rate, and residual symptoms between percutaneous endoscopic transforaminal discectomy (PETD) and percutaneous endoscopic interlaminar discectomy (PEID).

STUDY DESIGN

A comparative, retrospective, controlled trial.

SETTING

The study was conducted at the Department of Orthopaedics at a local hospital.

METHODS

From January 2015 to September 2020, consecutive patients who underwent PETD or PEID treatment for lumbar disk herniation (LDH) at the L5/S1 level in our department were retrospectively collected. Baseline data including age, gender, body mass index (BMI), smoking status, alcohol drinking, clinical symptoms, physical examination, and radiographic characteristics were documented. During the two to three year follow-up periods, patients were evaluated clinically, including clinical outcomes assessed by the visual analog score (VAS), patient satisfaction rates assessed by the North American Spine Society patient satisfaction index (PSI), recurrent rate, and residual symptoms.

RESULTS

A total of 113 patients with PELD in our department were included in the current study, with 65 patients in the PETD group and 48 in the PEID group. Demographic characteristics including age, gender, height, BMI, cigarette smoking, alcohol consumption status, and diabetes did not show any significant difference between the PETD and PEID groups. The VAS scores of the two groups were similar preoperatively, but the postoperative VAS score of the PEID group was lower than that of the PETD group. There were 90.8% of patients in the PETD group who were satisfied with the operation compared to 97.9% in the PEID group. The recurrence rate did not differ between groups, with three patients in both groups. Regarding residual symptoms, there were more patients in the PETD group who reported low back pain during the follow-up periods.

LIMITATION

The main limitations are that all patients were operated by the same surgical team from the same site, and there was a lack of multicenter data.

CONCLUSION

Both PETD and PEID have satisfactory patient-reported outcomes for treating LDH. The PEID procedure results in fewer low back pain residual symptoms than the PELD procedure.

Cost and Effectiveness of Percutaneous Endoscopic Interlaminar Discectomy versus Microscope-Assisted Tubular Discectomy for L5-S1 Lumbar Disc Herniation

OBJECTIVE

To assess the cost and effectiveness of percutaneous endoscopic interlaminar discectomy (PEID) and microscope-assisted tubular discectomy (MATD) for patients with L5/S1 lumbar disc herniation (LDH).

METHODS

The medical and financial records of patients diagnosed with L5/S1 LDH and who underwent either PEID or MATD from April 2021 to April 2022 were retrospectively collected. Demographic and baseline information, perioperative observational index, clinical outcomes, and inpatient costs were analyzed.

RESULTS

Sixty patients were included, with 30 patients in the PEID group and 30 patients in the MATD group. No significant difference was found in demographic and baseline information between the 2 groups (P > 0.05). The PEID group showed significantly shorter incision length, less intraoperative blood loss, shorter hospital stays, and higher intraoperative fluoroscopy frequency compared with the MATD group (P < 0.05). There were no significant differences in visual analog scale back/leg score, Oswestry Disability Index, and 36-Item Short-Form Survey score between PEID and MATD groups before the surgery and at any follow-up time points (P > 0.05). The total cost, surgery cost, and surgical instruments/materials cost were significantly higher in the PEID group compared with the MATD group (P < 0.05). In contrast, the drug and nursing costs were significantly higher in the MATD group than in the PEID group (P < 0.05).

CONCLUSIONS

PEID and MATD provide equivalent clinical efficacy and safety in treating LDH at L5/S1 segment within a 1-year follow-up. However, PEID is less invasive and MATD is less costly. No one surgical technique is superior in all aspects and patients should make decisions according to their top concern.

Clinical Outcomes of Percutaneous Endoscopic Interlaminar Discectomy Using a Laminotomy Technique With Modified Stepwise Local Anesthesia

BACKGROUND

Percutaneous endoscopic interlaminar discectomy (PEID) has been widely used in minimally invasive treatment of lumbar disc herniation (LDH) but is difficult to perform because of the narrow interlaminar window and painful for the patient. Therefore, further research is needed to find a safe and effective method to facilitate the development of PEID.

METHODS

Seventy-one consecutive patients with LDH who underwent PEID using a laminotomy technique with modified stepwise local anesthesia between July 2017 and June 2020. All patients were followed up for at least 6 months. Preoperative patient demographics, perioperative outcomes, and clinical outcomes were recorded. Visual Analog Scale (VAS) scores, Oswestry Disability Index (ODI) scores, and Macnab criteria were used to assess clinical results.

RESULTS

All patients underwent successful surgery under local anesthesia with no conversions to open surgery. The mean operation time was 79.56 ± 32.78 minutes and the average hospital stay was 6.44 ± 2.98 nights. Before surgery, the mean VAS score was 5.66 ± 1.206 and the mean ODI score was 68.41 ± 6.634; the respective scores were decreased to 0.65 ± 0.635 and 7.06 ± 1.594 after 4 weeks of follow-up (P < 0.001) and to 0.56 ± 0.691 and 7.11 ± 0.176 after 6 months (P < 0.001). According to the MacNab criteria, the outcome was excellent in 60 cases and good in the remaining 11 cases.

CONCLUSIONS

PEID via a laminotomy technique with stepwise local anesthesia is safe and effective for L4-5 and L5-S1 LDH.

Initial learning curve after switching to uniportal endoscopic discectomy for lumbar disc herniations

PURPOSE

The purpose was to investigate the learning curve for elective endoscopic discectomy performed by a single surgeon who made a complete switch to uniportal endoscopic surgery for lumbar disc herniations in an ambulatory surgery center and determine the minimum case number required to safely overcome the initial learning curve.

METHODS

Electronic medical records (EMR) of the first 90 patients receiving endoscopic discectomy by the senior author in an ambulatory surgery center were reviewed. Cases were divided by approach, transforaminal (46) versus interlaminar (44). Patient-reported outcome measures (visual-analog-score (VAS) and the Oswestry disability index (ODI)) were recorded preoperatively and at 2-week, 6-week, 3-month, and 6-month appointments. Operative times, complications, time to discharge from PACU, postoperative narcotic use, return to work, and reoperations were compiled.

RESULTS

Median operative time decreased approximately 50% for the first 50 patients then plateaued for both approaches (mean: 65 min). No difference in reoperation rate observed during the learning curve. Mean time to reoperation was 10 weeks, with 7(7.8%) reoperations. The interlaminar and transforaminal median operative times were 52 versus 73 min, respectively (p = 0.03). Median time to discharge from PACU was 80 min for interlaminar approaches and 60 min for transforaminal (p < 0.001). Mean VAS and ODI scores 6 weeks and 6 months postoperatively were statistically and clinically improved from preoperatively. The duration of postoperative narcotic use and narcotics need significantly decreased during the learning curve as the senior author realized that narcotics were not needed. No differences were apparent between groups in other metrics.

CONCLUSIONS

Endoscopic discectomy was shown to be safe and effective for symptomatic disc herniations in an ambulatory setting. Median operative time decreases by half over the first 50 patients in our learning curve, while reoperation rates remained similar without the need for hospital transfer or conversion to an open procedure in an ambulatory setting.

LEVEL OF EVIDENCE

Level III, prospective cohort.

Comparison of minimally invasive transforaminal lumbar interbody fusion and endoscopic lumbar interbody fusion for lumbar degenerative diseases: a retrospective observational study

BACKGROUND

Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) and endoscopic lumbar interbody fusion (Endo-LIF) are both minimally invasive interbody fusion procedures for lumbar degenerative diseases. In this study, we attempted to compare the clinical efficacy and postoperative outcomes of MIS-TLIF and Endo-LIF for lumbar degenerative diseases.

METHODS

The study cohort comprised 99 patients with lumbar degenerative diseases treated by MIS-TLIF or Endo-LIF from January 2019 to July 2021. The clinical outcomes (visual analogue scale (VAS), Oswestry disability index (ODI), and MacNab criteria) preoperatively, 1 month postoperatively, 3 months postoperatively, and 1 year postoperatively were compared between the two groups.

RESULTS

There were no significant differences between the two groups in sex, age, disease duration, affected spine segment, and complications (P > 0.05). The operation time was significantly longer in the Endo-LIF group than the MIS-TLIF group (155.25 ± 12.57 vs. 123.14 ± 14.50 min; P < 0.05). However, the Endo-LIF group had a significantly smaller blood loss volume (61.79 ± 10.09 vs. 259.97 ± 14.63 ml) and shorter hospital stay (5.46 ± 1.11 vs. 7.06 ± 1.42 days) than the MIS-TLIF group. In both groups, the ODI and VAS scores for lower back pain and leg pain were significantly lower at each postoperative timepoint than preoperatively (P < 0.05). Although there were no significant differences between the two groups in the ODI and VAS scores for lower back pain and leg pain (P > 0.05), the VAS for lower back pain was lower in the Endo-LIF group than the MIS-TLIF group at each postoperative timepoint. The MacNab criteria showed that the improvement rate was 92.2% in the MIS-TLIF group and 91.7% in the Endo-LIF group, with no significant difference between the two groups (P > 0.05).

CONCLUSIONS

There were no significant differences in short-term surgical outcomes between the MIS-TLIF and Endo-LIF groups. Compared with the MIS-TLIF group, the Endo-LIF group incurred less damage to surrounding tissues, experienced less intraoperative blood loss, and had less lower back pain, which is more conducive to recovery.

Tubular Microdiscectomy for Recurrent Lumbar Disc Herniation: A Valuable Alternative to Endoscopic Techniques

OBJECTIVE

The efficacy of tubular microdiscectomy (TMD) in the treatment of recurrent lumbar disc herniation (rLDH) is still unclear, especially compared with the endoscopic technique. We performed a retrospective study to analyze this question.

METHODS

We retrospectively included all patients with an rLDH confirmed by magnetic resonance imaging who underwent TMD between January 2012 and February 2019. The general data included sex, age, body mass index, level of rLDH, first surgical approach, reoperation interval, occurrence of dural leak, re-recurrence, and re-reoperation. The clinical outcome was evaluated using a visual analog scale for leg pain, and the modified MacNab criteria were used to evaluate patient satisfaction.

RESULTS

The visual analog scale score for leg pain was statistically significantly reduced from 7.46 preoperatively to 0.80 postoperatively (P < 0.00001), and the patient satisfaction was good or excellent in 85.7% of cases, according to the modified MacNab criteria. Complications occurred in 3 of the 15 included patients: 2 dural tears (13.3%) and 2 re-recurrence (13.3%), but none of the patients underwent a third surgical procedure.

CONCLUSIONS

TMD seems to be an efficient technique for the surgical treatment of leg pain caused by rLDH. In the literature, this technique seems to be at least as good as the endoscopic technique and is easier to master.

Early Postoperative Iatrogenic Neuropraxia After Lumbar Disc Herniation Surgery: Analysis of 87 Cases

BACKGROUND

Postoperative early neuropraxia after lumbar disc herniation surgery is common. The emergence of new paresthesia findings with increased sensory and motor deficits in the postoperative period suggests iatrogenic neuropraxia. This study aimed to discuss the causes and prognosis of iatrogenic neuropraxia detected in the early postoperative period in patients who have been operated on for lumbar disc herniation.

METHODS

Cases with postoperative iatrogenic neuropraxia were determined retrospectively. Deficits were evaluated at intervals of 0-2 hours, 2-12 hours, 12-24 hours, and 24-48 hours. The cases were evaluated in 2 groups as those who underwent aggressive discectomy and simple discectomy. In addition, the treatment results were compared between the 2 groups as the cases that were treated and not treated with methylprednisolone.

RESULTS

The iatrogenic neuropraxia rate was significantly higher in patients who underwent aggressive discectomy. Although it was observed that paresthesia findings improved more rapidly in cases treated with methylprednisolone, no difference was found between the 2 groups in terms of its effects on the motor deficit.

CONCLUSIONS

Iatrogenic neuropraxia is a finding whose cause cannot be determined by quantitative criteria. It is common in patients who underwent aggressive discectomy. Methylprednisolone treatment is effective in recovering the paresthesia finding faster and may show that the radicular injury is in the neuropraxia stage in the early period.

Learning Curve and Complications of Unilateral Biportal Endoscopy: Cumulative Sum and Risk-Adjusted Cumulative Sum Analysis

OBJECTIVE

The purpose of this study was to investigate the learning curve and complications of unilateral biportal endoscopy (UBE) in the treatment of lumbar disc herniation (LDH) and lumbar spinal stenosis (LSS).

METHODS

This was a retrospective cohort analysis of 197 consecutive patients who received UBE unilateral laminotomy bilateral decompression (UBE-ULBD) or lumbar discectomy (UBE-LD) surgery, including 107 males and 90 females with an average age of 64.83 ± 14.29 years. Cumulative sum (CUSUM) and risk-adjusted cumulative sum analysis (RA-CUSUM) were used to evaluate the learning curve, with the occurrence of complications defined as surgical failure, and variables of different phase of the learning curve were compared.

RESULTS

The cutoff point of learning curve of UBE surgery was 54 cases according to CUSUM analysis. The learning curve of UBE-ULBD and UBE-LD were divided into 3 phases. The first cutoff points were 31 and 12 cases, and the second cutoff point were 67 and 32 cases respectively. With the progress of the learning curve, the operation time and postoperative hospital stays decreased. The visual analogue scale and Oswestry Disability Index at the last follow-up were significantly lower than that before surgery. The incidence of surgical failure was 6.11% and began to decrease after the 89th case based on RA-CUSUM analysis. The surgical failure rate decreased from 10.11% to 2.78 after the 89th case with significant different.

CONCLUSION

UBE surgery is effective in the treatment of LDH and LSS with low incidence of complications. But a learning curve of at least 54 cases still required for mastering UBE surgery.

Full-Endoscopic versus Minimally Invasive Lumbar Interbody Fusion for Lumbar Degenerative Diseases : A Systematic Review and Meta-Analysis

OBJECTIVE

Although full-endoscopic lumbar interbody fusion (Endo-LIF) has been tried as the latest alternative technique to minimally invasive transforaminal lumbar interobody fusion (MIS-TLIF) since mid-2010, the evidence is still lacking. We compared the clinical outcome and safety of Endo-LIF to MIS-TLIF for lumbar degenerative disease.

METHODS

We systematically searched electronic databases, including PubMed, EMBASE, and Cochrane Library to find literature comparing Endo-LIF to MIS-TLIF. The results retrieved were last updated on December 11, 2020. The perioperative outcome included the operation time, blood loss, complication, and hospital stay. The clinical outcomes included Visual analog scale (VAS) of low back pain and leg pain and Oswestry disability index (ODI), and the radiological outcome included pseudoarthosis rate with 12-month minimum follow-up.

RESULTS

Four retrospective observational studies and one prospective observational study comprising 423 patients (183 Endo-LIF and 241 MIS-TLIF) were included, and the pooled data analysis revealed low heterogeneity between studies in our review. Baseline characteristics including age and sex were not different between the two groups. Operation time was significantly longer in Endo- LIF (mean difference [MD], 23.220 minutes; 95% confidence interval [CI], 10.669-35.771; p=0.001). However, Endo-LIF resulted in less perioperative blood loss (MD, -144.710 mL; 95% CI, 247.941-41.478; p=0.023). Although VAS back pain at final (MD, -0.120; p=0.586), leg pain within 2 weeks (MD, 0.005; p=0.293), VAS leg pain at final (MD, 0.099; p=0.099), ODI at final (MD, 0.141; p=0.093) were not different, VAS back pain within 2 weeks was more favorable in the Endo-LIF (MD, -1.538; 95% CI, -2.044 to -1.032; p<0.001). On the other hand, no statistically significant group difference in complication rate (relative risk [RR], 0.709; p=0.774), hospital stay (MD, -2.399; p=0.151), and pseudoarthrosis rate (RR, 1.284; p=0.736) were found.

CONCLUSION

Relative to MIS-TLIF, immediate outcomes were favorable in Endo-LIF in terms of blood loss and immediate VAS back pain, although complication rate, mid-term clinical outcomes, and fusion rate were not different. However, the challenges for Endo-LIF include longer operation time which means a difficult learning curve and limited surgical indication which means patient selection bias. Larger-scale, well-designed study with long-term follow-up and randomized controlled trials are needed to confirm and update the results of this systematic review.

Comparative study of the efficacy and safety of minimally invasive interlaminar full-endoscopic discectomy versus conventional microscopic discectomy in single-level lumbar herniated intervertebral disc (ENDO-F Trial): a multicenter, prospective, randomized controlled trial protocol

Background

Advances in minimally invasive surgery have expanded the indications for interlaminar full-endoscopic discectomy. Although the clinical outcomes for this approach may be equivalent to those of conventional microscopic discectomy, the supporting evidence is still based on small, single-center, prospective, and retrospective studies. Therefore, a multicenter randomized controlled trial is warranted.

Methods

This will be a prospective, multicenter, randomized controlled trial comparing the efficacy and safety of interlaminar full-endoscopic discectomy to those of conventional microscopic discectomy. The trial will enroll 100 participants with a lumbar disc herniation, 50 in each group. The primary outcome will be the Oswestry Disability Index (ODI) score at 12 months post-surgery. Secondary outcomes will be back and leg pain (visual analog scale); the ODI; the EuroQol-5-dimension score; patient satisfaction; and walking distance/time and time to return to daily activities post-surgery. Surgical outcomes will include postoperative drainage, operative time, duration of hospital stay, postoperative creatine kinase level as an indicator of muscle injury, and postoperative scarring. Postoperative magnetic resonance imaging, computed tomography, and simple radiography will be performed to evaluate radiographic outcomes between the two surgical approaches. Surgery-related complications and adverse effects will be evaluated as safety outcomes. A single assessor at each participating hospital, blinded to group allocation, will assess the enrolled participants at baseline, at 2 weeks, and at 3, 6, and 12 months postoperatively.

Discussion

This trial is designed to determine whether interlaminar full-endoscopic discectomy is clinically comparable to microscopic discectomy to treat lumbar disc herniations. All efforts will be made to reduce bias, including adequate sample size, blinded analyses, and multicenter prospective registration. The outcomes will inform practice, providing the evidence needed for using interlaminar full-endoscopic over microscopic discectomy by confirming the potential of this technique to improve patient satisfaction and clinical outcomes.

Trial registration: Clinical Research Information Service; cris.nih.go.kr. (KCT0006277); protocol version (v1, June 8, 2021).

The 20 most important questions for novices of full-endoscopic spinal surgery in China: a mixed-method study protocol

INTRODUCTION

The full-endoscopic spinal surgery (FESS) procedure is widely accepted and welcomed in China. With the continuous development of minimally invasive surgery, the further expansion of indications and the greater diversity of techniques, spinal endoscopic surgery currently accounts for more than 10% of spinal surgery in China, ranking among the top in the world. However, the admission system and standardised training system for spinal endoscopic surgery are not perfect, which presents a challenge and disadvantage for novices.

METHODS AND ANALYSIS

Exploratory mixed methods are applied for designing this study. First, we will collect questions from novices by allowing them to openly list their concerns to those who have completed FESS. These qualitative questions will be categorised using NVivo software. To produce the qualitative results, a questionnaire for the sequential two-round Delphi approach will be developed to identify the 20 most important questions from novices. This study is planned to be started at April 2021, and completed at March 2022.

ETHICS AND DISSEMINATION

The Research Ethics Committee of Peking University Third Hospital provided a waiver for this Delphi protocol. We expect that the findings will be published in a clinical journal and presented at conferences. Furthermore, we hope that the results can contribute to answering the questions raised by novices of spinal endoscopy in the form of books and to improving the training system for spinal endoscopy surgery.

Percutaneous Transforaminal Endoscopic Discectomy Versus Open Microdiscectomy for Lumbar Disc Herniation: A Systematic Review and Meta-analysis

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVE

To give a systematic overview of effectiveness of percutaneous transforaminal endoscopic discectomy (PTED) compared with open microdiscectomy (OM) in the treatment of lumbar disk herniation (LDH).

SUMMARY OF BACKGROUND DATA

The current standard procedure for the treatment of sciatica caused by LDH, is OM. PTED is an alternative surgical technique which is thought to be less invasive. It is unclear if PTED has comparable outcomes compared with OM.

METHODS

Multiple online databases were systematically searched up to April 2020 for randomized controlled trials and prospective studies comparing PTED with OM for LDH. Primary outcomes were leg pain and functional status. Pooled effect estimates were calculated for the primary outcomes only and presented as standard mean differences (SMD) with their 95% confidence intervals (CI) at short (1-day postoperative), intermediate (3-6 months), and long-term (12 months).

RESULTS

We identified 2276 citations, of which eventually 14 studies were included. There was substantial heterogeneity in effects on leg pain at short term. There is moderate quality evidence suggesting no difference in leg pain at intermediate (SMD 0.05, 95% CI -0.10-0.21) and long-term follow-up (SMD 0.11, 95% CI -0.30-0.53). Only one study measured functional status at short-term and reported no differences. There is moderate quality evidence suggesting no difference in functional status at intermediate (SMD -0.09, 95% CI -0.24-0.07) and long-term (SMD -0.11, 95% CI -0.45-0.24).

CONCLUSION

There is moderate quality evidence suggesting no difference in leg pain or functional status at intermediate and long-term follow-up between PTED and OM in the treatment of LDH. High quality, robust studies reporting on clinical outcomes and cost-effectiveness on the long term are lacking.Level of Evidence: 2.

Learning Curve for Interlaminar Endoscopic Lumbar Discectomy: A Systematic Review

BACKGROUND

Interlaminar endoscopic lumbar discectomy (IELD) is an efficient surgical treatment for lumbar disc herniation. However, this minimally invasive procedure requires a considerable learning curve that has not yet been standardized. This review aimed to evaluate the learning curve's characteristics, including the cutoff point required to achieve technical proficiency and to discuss appropriate training methods.

METHODS

We systematically searched the core databases (PubMed, Embase, and Cochrane Library) for clinical studies that evaluated the learning curve using quantitative data. We performed a quality assessment using the Newcastle-Ottawa scale. We also compared descriptive statistics, including operative time and other variables before and after the cutoff point.

RESULTS

Six studies reporting 302 cases of IELD were selected from 7188 screened articles. The cutoff point was randomly set in 3 studies and determined as the curve's asymptote in 3 studies. The mean value for the cutoff point was 22.17 ± 12.40 cases (range: 10-43 cases) and mainly determined based on the operative time, which was shorter in the late group than that in the early group (P < 0.05). The cutoff points were not significant for patient outcome parameters such as pain score, functional result, surgical failure, or complications.

CONCLUSIONS

The evidence of published studies regarding the learning curve for the IELD technique is insufficient. The reported cutoff points may be significant only for task efficiency. Moreover, they may not represent the asymptote of the curve. Future studies should evaluate the actual plateau points using patient outcome data.

Learning curve of percutaneous endoscopic transforaminal lumbar discectomy by a single surgeon

To evaluate the learning curve of percutaneous endoscopic transforaminal lumbar discectomy (PETLD) from the novice stage to the proficient stage, we performed retrospective study for patients with lumbar disc herniation who underwent PETLD performed by a single surgeon and evaluated the surgeon's learning curve and the effect of surgical proficiency on outcomes.A total of 48 patients who underwent PETLD at the lower lumbar level (L3-S1) with a minimum 1-year follow-up were enrolled. The learning curve of the surgeon was assessed using cumulative study of operation time and linear regression analyses to reveal the correlation between operation time and case series number.Because the cutoff of familiarity was 25 cases according to the cumulative study of operation time, the patients were allocated into two groups: early group (n = 25) and late group (n = 23). The clinical, surgical, and radiological outcomes were retrospectively evaluated and compared between the two groups.According to linear regression analyses, the operation time was obtained using the following formula: operation time (minutes) = 69.925-(0.503 × [case number]) (P < .001).As expected, the operation time was significantly different between the two groups (mean 66.00 ± 11.37 min in the early group vs 50.43 ± 7.52 min in the late group, P < .001). No differences were found between the two groups in demographic data and baseline characteristics. Almost all clinical outcomes (including pain improvement and patient satisfaction), surgical outcomes (including failure, recurrence, and additional procedure rates), and radiological outcomes (including change of disc height and sagittal angles) did not differ between the two groups.However, the late group demonstrated a more favorable postoperative volume index of the remnant disc (362.91 mm3 [95% confidence interval, 272.81-453.02] in the early group vs 161.14 mm3 [95% confidence interval, 124.31-197.97] in the late group, P < .001), and a lower complication rate related to exiting nerve root (16.0% in the early group vs 0% in the late group, P = .045).The learning curve of PETLD is not as difficult as that of other minimally invasive spine surgery technique. Although the overall outcomes were not different between the groups, the risks of incomplete decompression and exiting root injury-related complication were higher in the novice stage.